I knew ice baths had attained a certain cultural status in the fitness realm when I saw a friend getting into a barrel filled with ice water outside of his garage gym after training. Maybe it’s the mythical nature of the pain that has made it so popular. It seems to have a certain appeal to endure agony even while you’re recovering from exercise.

In the study, 24 participants were placed in one of three groups: a control group, a group doing ice water emersion, or a group doing contrasting hydrotherapy, which mixes hot and cold water immersion. The participants played a game of rugby and immediately afterward did one of these protocols. The researchers took measurements before the game and at five different intervals after the game, the final one being a full six days later. They measured jumping ability, sprinting ability, flexibility, muscle circumference, and how the athletes felt in regards to their muscle soreness.

In all groups there were trends toward recovery at the 48-hour mark, but there was measurable fatigue from the game even six days later. Of the variables they tested, only flexibility was universally improved at the six-day mark. As far all the other variables, only perceptions of soreness and effort were affected by the hydrotherapy in this study. In both forms of hydrotherapy, muscle soreness was reduced, but in the contrasting group their perceptions of exertion actually went up.

The remaining variables that did not seem to be improved were performance related, such as power output in a jump and sprinting. Because the actual performance of athletic variables wasn’t affected by either better recovery or improvements in feelings of soreness, it may mean there is no good reason to do hydrotherapy. In fact, the idea of the mythical status of hydrotherapy that I mention above might simply be a product of feelings of reduced soreness.

All that said, in principle, manipulating temperature is one of the most basic theoretical ways to change blood flow. Improving blood flow post exercise seems like a no brainer. After exercise you have restricted blood flow due to the swelling of tissue. Cold reduces swelling, at least near the surface of the skin and for a little bit. Heat, on the other hand, increases blood flow. The two put together ought to be a good thing for athletic recovery.

While the results of this study are clear, I’m not ready to give up on hydrotherapy just yet. With a theory for its effectiveness as simple as how temperature affects the human body, it seems to stand on strong enough ground to withstand one study. And, since there are some benefits at least to how it makes us feel, there’s good reason to do it anyway.

If you’re able to easily perform hydrotherapy, even if that amounts to contrasting the temperature in your shower, I’d still with it until more research comes out explaining the mechanisms for why it wouldn’t work.